The present invention relates to the art of aviational spraying of agricultural crops.
Spraying of agricultural crops by airplanes is traditionally known and is performed by a light airplane flying low over a field and releasing therebehind a "vapour trail" of fine droplets of a chemical preparation such as insecticide. The spraying is effected by a series of especially designed spraying jets, the jets being mounted to and in communication with an elongated spray boom, carrying the chemical preparation in liquid form. The boom extends alongside and somewhat lower than the trailing edge of both airplane wings.
It has been already recognized that the conventional method of airborne spraying--despite its obvious advantages--is in some respects less effective than the manual or vehicular, on-site spraying methods, whereby the chemical preparations are directly applied to the desired location around the stems of the crop.
Thus, in aviational spraying considerable proportions of the total quantity of chemical preparation sprayed in the vapour trail are often blown off target, i.e. away from the area to be sprayed, by prevailing breezes, the occurrence of which not only results in a waste of costly materials and time, but also has a negative ecological impact on and may damage neighboring fields, particularly in cases where herbicides are sprayed.
Secondly, since the droplets descend by gravity only, a significant amount thereof merely rests on the leaves or the boughs of the plants, rather than penetrates down to the ground, near the crop stems as required for insecticidal or other effects.